Friction shock absorbing mechanisms for railway draft riggings



G. E. DATH June 8, 1948.

v FRICTION SHOCK ABSORBING MECHANISMS FOR RAILWAY DRAFT RI GGINGS 2Sheets-Sheet 1 InverzZar 'eal yez. 342% Filed Feb. 8, 1945 Patented June8, 1948 FRICTION sHocK ABSQBBINQ msMs ORBAILWAY HE F BIQQ N GeorgeE.Dath,Mokena, Ill., assignonto WnH.

Mlner, 7 Inc., Chicago, Ill.,

a. corporation of A i ation F b ua 8, 9 fie lie N -v. 3 3

;8 Claims. "1 Ihis invention relates to improvements '-in frictipn'shock absorbing mechanisms especially adapted i or-railwaydraftriggings.

' Qne object of the invention is to provide a friction sh'ock absorbingmechanism including a 1' column element and a cooperating springresisted frictionclutch sli dable lengthwise' c'f -said column 'elementwherein-grippin action of the clutch; is delayed until the ineohanism isI compressed to a predetermined; extent to provide preliminary springaction for absorbing the lighter shocks followed by high frictionalresistance by gripping action of the clutch to absorb the heaviershocks.

further object of; the invention is toprovide a' mechanism as set forthin the preceoling paragraphwherein the ifriction clutchin-cludes -aplurality pf friction shoes and a wedge membrior wedgingthe-shoes intotightfrictional engagement with the column element, and the spring meanswhich resists inward movement of the clutch; includes separate springmembers independently --resisting inward movement of the shoesand: wedgerespectively,- there beings, predetermined amount of lost motion'between-the shoes and the spring member 'which cooperates therewith to providefor the preliminary spring actionofthemechanism bycompression of thespring which cooperates-with the-wedgemember andI-produoes the heavierfrictional resistance after-the lost motion between the shoesand springwhich cooperateswith the shoeshas been e nup- A -more specificobjectofthe invention is to provide a friction; shock absorbin mechanismcomprising a friction casing; friction shoes sliding lv telescopedwiththe casing; a pressure transmitting wedge block -movable inwardlyof thecasing and having wedging engagement-with the shoes; a springmember-reacting between the casing and-the wedge yieldingly opposinginward-movement of the wedge only; an additional springmember-yieIdingIy opposing inward movement-pf the shoes;- and aspringfollower interposed between the -secondnamed spring and shoes whereinthespring:- follower. isnormally held -spacedt-inwardly irom the shoes to apermit inward movement-of thewedseblock and'shoes to apredetemninedoextentbefore the shoesiactivelvengage:--the-=spring-'follower ,to compress v t i2 said I additional spring, thereby providinginitial light spring actibnfluring relative movemenirof the shoes andspringfollowerj followedby high frictional resistance duringthe-rernainder ofsthe compressionstroke.

Other objectsof the invention-will more clearly appear fromthedesc-ription andlclaimsi'hereihafter following.

In the. drawingsforming a. part Of:.thl'S specification, FigureLisa-front.elevationalflview oimy improved friction i shock; absorbing 4mechanism. Figure 2 is alongitudinal', vertical sectional view,corresponding substantially to the line 22: of Figurel. .iFigureiltis.,a transverse, verticalsectional .view, 1 corresponding substantiallyto, the line 3-1-3 o.Figure=-2. figure 4 is .a. rear -.elev ational viewof .the, wedge .block, .of, my improved mechanism, looking; iromright.tQlGfijIlTfiiZl 2. .eFigure dis a view similar toz-Ffigure ZJShQWiHthetmechanism partly compressed. -1={igure 6, is a YieW Similar"tOTFZI-IIQZ,- il1l15tla tillg shenanoner or assemblin the. mechanis Asv.sh-own .in. the, drawing hmy im mvedofri .tion ..-sho ck labsorbingtme hanism comprises broadly a. {friction casin nA; a W d e bl ck-:4three friction :shoes CTCTCL a, ma n; sp in 11 sistance: D a. preliminay. sprin resista fi e and aspring followerring F.

The c si A i t nxtheo orm o a .tzuhula frees mg, haVingcth .-W 1 1 atthii ont e d ,the e m wardly thi kened, ther by prpvid n th ftriqfiiq.shellsectionzi 0; f th fiasine- .1 Reervardl Pi th friction shell.section o .10, t e. ca i g ov de .a spring ca po ti n nwhic l cfsuh iemell cylindrical cross section. The trt ar endof t e casing 1A; i closedthreefle lieis mb which .iorms th marvel-l2 o t ee lo irhe iri t o isthesectionl o the neiseihese ,ona1.,;-t e ver .crossefitti ya 1. 1l!@ 21.thickenedwailsthfirtofi prqvide a transversestop s d ll i att e innr-endort e shellseqtio twhifihselwfissfi a tro tswizf n mitip o. W rmovement of.- 171718.;SPI1115-"15Q110W61 jringiF. DThe i i e l s cti n Jre en s. th ee lon tud vnally extending, interior fri ction suriaces lll4ll 4 whichrarehof VV-.shaped, v.tra'rlsli lfs crcsssection. t Atct eopen.frQ tend,-th tis;. torwardly. 0f the triction .suriaces J 4 ot-,the ea ing, the. casing-1. is provided: with. an .intumedrstq flange J5 adapted to; limit outward/ mov m n 3 of the friction shoes C-C-C, ashereinafter pointed out. The inneredge of the flange [5 defines a trulycircular opening IS.

The wedge B is in the form of a hollow block of generally cyclindrical,transverse cross section, having a flat, transverse, front end face I!adapted to be engaged by the usual follower of the railway draftrigging. At the rear end portion thereof, the wedge block B is providedwith three wedge faces l8--l8l8 of V-shaped, transverse cross section,which are arranged symmetrically about the longitudinal axis of themechanism and converge inwardly. Rearwardly of the wedge faces I8-l8-l8,the wedge block B is provided with a hollow, tubular extension [9,-

having a laterally outwardly extending flange 20 at its rear end. Theflange 20 is preferably of circular outline. The flange 20 presents aflat end face 2 I, which serves as an abutment for the front end of thepreliminary spring E,

The friction shoes C-C-C are three in number 4 by applying the screwthreaded disc l2, which forms the rear wall thereof.

The operation of my improved friction shock absorbing mechanism is asfollows: Upon compression of the mechanism between the front and rearfollowers of the railway draft rigging, the wedge block B is forcedinwardly of the casing against the resistance of the preliminary springE, and the friction shoes-are carried inwardly with the wedge block.During the described action, there is no frictional resistance producedbetween the friction shoes and the friction surfaces of the casing Ainasmuch as inward movement of the shoes is unopposed by any resistancemeans. A light preliminary spring action is thus produced. As the wedgeB and the shoes CC-C continue to move inwardly of the casing, duringfurther compression of the mechanism, the shoes engage and pickup thespring: follower ring F, thereby comand surround the rear end portion ofthe wedge block B. Each shoe C is of V-shaped, transverse section andhas an outer friction surface 22 which is of V-shaped, transverse crosssection and is adapted to engage with one of the V-shaped frictionsurfaces M of the casing A. On the inner side, each shoe 0 is providedwith a V-shaped wedge face 23, which is engaged with the correspondingV-shaped wedge face l8 of the block B.

As will be evident, the wedge block B, together with the friction shoesC-C-C, form an expandible clutch which is slidingly mounted within thefriction casing A, the clutch being in contracted condition in thenormal position of the parts with clearance between the frictionsurfaces of the shoes and the friction surfaces of the casing.

The spring follower F is in the form of a flat, disclike member having acentral, circular opening 24, adapted to freely accommodate the circularflange of the wedge block B. The spring follower F, which is in the formof a ring, normally bears against the shoulder l3 of the casing A. Thespring follower F is thus restricted in its outward movement withrespect to the casing A to hold the same normally spaced inwardly fromthe inner ends of the friction shoes C-C--C'.

The main spring resistance D is in the form of a heavy helical coil,which surrounds the spring E. The spring D is interposed between thespring follower ring F and the rear wall l2 of the casing and has itsfront and rear ends bearing directly on said spring follower and casingwall.

The preliminary spring E is in the form of a relatively light coil,extending through the opening 24 of the spring follower ring F andhaving its front and rear ends bearing respectively on the rear end face2| of the wedge block B and the end wall l2 of the casing A.

In assembling the mechanism, the parts are all inserted through the rearend of the casing A, the clutch comprising the wedge B, assembled withthe shoes C-CC, being first inserted. As shown most clearly in Figure 6,the clutch in contracted condition is of such a size as to pass freelybetween the rear end portions of the friction surfaces I:lI l--|4 of thecasing A. After the clutch has been inserted, it is moved forwardlyuntil the shoes are shouldered against the flange l5 of the casing. Thespring follower ring F and the springs D and E are then placed withinthe casing, the spring follower ring being placed in abutment with theshoulder I3. After the parts have been completely assembled, the casingis closed pressing the spring D during the remainder of the compressionstroke of the mechanism. Due to the resistance offered by the spring D,a wedging action is set up between the wedge block B and the frictidnshoes CC-C, and the shoes are spread apart and forced into tightfrictional contact with the friction surfaces of the casing. Highfrictional resistanceis thus produced during the last described action,thereby taking care of the heavier shocks to which the mechanism issubjected. When the actuating'force is reduced,;the expansive action ofthe springs D and E returns all of the parts to the normal full releaseposition shown in Figure 2, the spring D forcing the spring followerring F outwardly until limited by the shoulder 13 of the casing A andthe spring E forcing the wedge outwardly until outward movement thereofis limited by engagement of the friction shoes C-C-C with the flange l5of the casing A, outward movement of the wedge block B with respect tothe shoes being positively limited by engagement between the flange 20of the wedge block and the shoes C-C-C. As will be evident, the shoesC-C-C are carried forwardly in unison with the wedge block B byshouldered engagement with the flange 20.

I claim:

1. In a friction shock absorbing mechanism, the combination with acolumn element having lengthwise extending friction surfaces; of afriction clutch slidable lengthwise of said element, said clutchincluding a wedge pressure transmitting member and friction shoescooperating with the friction surfaces of said element, said pressuretransmitting member and shoes having cooperating wedge faces; a springyieldingly opposing inward movement of said wedge member only; yieldingmeans cooperating with said shoes; and means on said wedge engaging saidshoes to move the same outwardly in unison with the wedge away from saidyielding means during expansion of the mechanism, said shoes beingmovable inwardly of said column element with said wedge member, byengagement of said wedge faces thereof, toward and into engagement withsaid yielding means to compress the same, thereby setting up wedgingaction between said wedge member and shoes to force the shoes into tightfrictional engagement with the column element.

2. In a friction shock absorbing mechanism, the combination with afriction casing having interior friction surfaces; of a friction clutchslidingly telescoped within the casing, said clutch including a centralwedge member and friction shoes surrounding said wedge member andmovable inwardly and outwardly of the casing thereamazes with; aspring'follower; means: for limiting outber; has been forcedinwardlyrtopredeterm n extent, thereby settin iup wedging action :be-

tween the wedge and shoes; and a second spring bearing directly on saidwedge and reacting between said wedge and casing directly resistinginward movement of the wedge throughout the entire compression stroke ofthe mechanism.

3. In a friction shock absorbing mechanism, the combination with afriction column element having longitudinally extending frictionsurfaces; of a friction clutch slidable lengthwise of said element, saidclutch including a wedge member adapted to receive the actuating force,and cooperating friction shoes movable inwardly and outwardly of saidelement with said member; a spring follower; means for limiting outwardmovement of said spring follower and normally holding the same spacedinwardly from said shoes; a spring yieldingly resisting inward movementof said spring follower, said shoes being movable inwardly of saidelement with said wedge member toward said spring follower to engage andforce the same inwardly against the resistance of said spring after themechanism has been partly compressed and the wedge member has been movedinwardly to a predetermined extent, thereby setting up wedging actionbetween the wedge and shoes; and a second spring bearing directly onsaid wedge and reacting between the wedge and column element directlyresisting inward movement of said wedge throughout the compressionstroke of the mechanism.

4. In a friction shock absorbing mechanism, the combination with atapered friction casing having interior, inwardly converging frictionsurfaces; of a plurality of friction shoes slidable within the casingand being engageable with said friction surfaces; a pressuretransmitting wedge member movable inwardly and outwardly of the casing,said member and shoes having cooperating wedge faces; a spring followerhaving shouldered engagement with the casing to limit outward movementthereof and hold the same normally spaced inwardly from said shoes; aspring bearing directly on said wedge and reacting between said casingand wedge for yieldingly opposing inward movement of the wedgethroughout the compression stroke of the mechanism; and a second springreacting between said casing and spring follower yieldingly opposinginward movement of said follower, said shoes being movable inwardly ofthe casing with said wedge member and toward said spring follower toengage and force the latter inwardly of the casing after said wedgemember has been forced inwardly to a predetermined extent, therebysetting up wedging action between said member and shoes to force theshoes into tight frictional engagement with the casing.

5. In a friction shock absorbing mechanism, the combination with atapered friction casing having inwardly converging, interior frictionsurfaces; of a friction clutch slidingly telescoped within the casing,said clutch including a cen- =traltwedgememberandifrictionshoeszsurround- -ing said .twedge-ranemberzandsmovable inwardly land ,outwardlyofzthe casingtherewith lengthwise-:of":'said :friction asurfaces; iaispring ifoll w r;

:means for :wlimiting luoutward :movement i of said =spring:followereandxnormallyeholding: the-rsame spaced;- from saidshoes i a:spring yieldinglyere- :sisting inward-movement of saidaspring follower,-saidgshoes :beingimoizablei inwardlycoftheecasing with said ..wedgezimember: toward :and rinto ;engagementwi-th:the;springzfollowerttoiforce said ffollowert-inwardlyagainstfjtheeresistance'lofisaid spring :after i the omechanism ehasLubeen epartly compressed, thereby setting up wedging action between thewedge and shoes; and a second spring bearing directly on said wedge andreacting between said wedge and casing throughout the compression strokeof the mechanism directly resisting inward movement of the wedge.

6. In a friction shock absorbing mechanism, the combination with' afriction casing; of a wedge pressure transmitting member movableinwardly of the casing; a spring bearing directly on said member toyieldingly oppose inward movement of said member; a spring followerwithin the casing; spring means yieldingly opposing inward movement ofsaid spring follower; and a friction shoe movable inwardly of the casingwith said member and towards said spring follower to engage and forcethe same inwardly of the casing against the resistance of said springmeans, thereby setting up wedging action between said member and shoe toforce the shoe into tight frictional engagement with the casing.

7. In a friction shock absorbing mechanism, the combination with acolumn element having friction surfaces extending lengthwise thereof; ofa pressure transmitting wedge member movable lengthwise of said columnelement; a spring bearing directly on said wedge member and reactingbetween said column element and wedge member opposing inward movement ofthe latter throughout the compression stroke of the mechanism; a springfollower having shouldered engagement with said element to limit outwardmovement of the spring follower; a second spring reacting between saidcolumn element and spring follower, yieldingly opposing inward movementof said spring follower; and friction shoes having lengthwise slidingmovement with respect to said element, said shoes and wedge havingcooperating wedge faces, said shoes having their inner ends normallyspaced from said spring follower, said shoes being engaged by said wedgemember and movable inwardly with said member and towards said springfollower to engage and force the same inwardly of the casing against theresistance of said second named spring, thereby setting up wedgingaction between said member and shoes to force the latter into tightfrictional engagement with said element.

8. In a friction shock absorbing mechanism, the combination with afriction casing having interior friction surfaces; of a pressuretransmitting wedge member movable inwardly and outwardly of the casing;a spring bearing directly on said wedge member and reacting between saidcasing and wedge member to yieldingly oppose inward movement of saidwedge throughout the compression stroke of the mechanism; a springfollower having shouldered engagement with the casing to limit outwardmovement thereof; a second spring reacting between said casing andspring follower yieldingly opposing inward movement of said springfollower; and a plurality of Vfrictionshoes slidable lengthwise withinthe casing, said shoes and wedge having cooperating wedge faces, saidshoes having their inner ends normally spaced outwardly away from saidspring follower, said shoes being engaged by said wedge member andmovable inwardly with said memher and towards said spring follower toengage the inner ends of said shoes with said spring follower and forcesaid spring follower inwardly of the casing against the resistance. ofsaid second named spring, thereby setting up wedging action between saidmember and shoes to force the lat- 8 ter into tight frictionalengagement with said casing. V

GEORGE E. DATH.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

